Add helper function to add CSS from a resource

This project keeps a number of CSS files next to the widgets they apply
to. (You might expect from the current layout that they apply only to
the page at hand, but in fact they are global.)

Libadwaita can automatically load certain resources, but not when
arranged in this way. It may in future be desirable to centralize all
CSS rules in one file, and namespace them better.

https://gnome.pages.gitlab.gnome.org/libadwaita/doc/main/styles-and-appearance.html#custom-styles

In the meantime, add a helper function to load CSS from a resource and
install it for the default display.

4 files changed, 54 insertions, 0 deletions

diff --git a/gnome-initial-setup/gis-util.c b/gnome-initial-setup/gis-util.c
new file mode 100644
index 0000000..ac153fc
--- /dev/null
+++ b/gnome-initial-setup/gis-util.c
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2023 Endless OS Foundation LLC
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <gtk/gtk.h>
+
+#include "gis-util.h"
+
+void
+gis_add_style_from_resource (const char *resource_path)
+{
+  g_autoptr(GtkCssProvider) provider = gtk_css_provider_new ();
+
+  gtk_css_provider_load_from_resource (provider, resource_path);
+  gtk_style_context_add_provider_for_display (gdk_display_get_default (),
+                                              GTK_STYLE_PROVIDER (provider),
+                                              GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+}
diff --git a/gnome-initial-setup/gis-util.h b/gnome-initial-setup/gis-util.h
new file mode 100644
index 0000000..5041bdd
--- /dev/null
+++ b/gnome-initial-setup/gis-util.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2023 Endless OS Foundation LLC
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+void gis_add_style_from_resource (const char *path);
diff --git a/gnome-initial-setup/gnome-initial-setup.h b/gnome-initial-setup/gnome-initial-setup.h
index 8880634..2865867 100644
--- a/gnome-initial-setup/gnome-initial-setup.h
+++ b/gnome-initial-setup/gnome-initial-setup.h
@@ -35,6 +35,7 @@ typedef struct _GisPage      GisPage;
 #include "gis-page.h"
 #include "gis-pkexec.h"
 #include "gis-keyring.h"
+#include "gis-util.h"
 
 void gis_ensure_stamp_files (GisDriver *driver);
 gboolean gis_get_mock_mode (void);
diff --git a/gnome-initial-setup/meson.build b/gnome-initial-setup/meson.build
index a3dd513..a6a014d 100644
--- a/gnome-initial-setup/meson.build
+++ b/gnome-initial-setup/meson.build
@@ -16,6 +16,7 @@ sources += [
     'gis-pkexec.c',
     'gis-driver.c',
     'gis-keyring.c',
+    'gis-util.c',
     'gnome-initial-setup.h',
     'gis-assistant.h',
     'gis-page.h',